Endodontic Working Length Measurement Using Cone-beam Computed Tomographic Images Obtained at Different Voxel Sizes and Field of Views, Periapical Radiography, and Apex Locator: A Comparative Ex Vivo Study

Abstract

IntroductionThe aim of this study was to evaluate the accuracy of working length determination by using an electronic apex locator, periapical radiography, and cone-beam computed tomographic (CBCT) imaging obtained at different voxel sizes and field of views (FOVs) in extracted human teeth. MethodsThirty extracted human mandibular premolar teeth were used. The electronic working length measurements were performed by using an electronic apex locator (Root ZX; J Morita Corp, Kyoto, Japan). Five different image sets were obtained as follows:(1) CBCT imaging: 40 × 40 mm FOV, 0.080 mm3 (FOV40);(2) CBCT imaging: 60 × 60 mm FOV, 0.125 mm3 (FOV60);(3) CBCT imaging: 80 × 80 mm FOV, 0.160 mm3 (FOV80);(4) CBCT imaging: 100 × 100 mm FOV, 0.250 mm3 (FOV100); and(5) periapical digital radiography. Direct measurements performed with an electronic digital caliper were considered as the gold standard and compared with the electronic apex locator, CBCT, and periapical image measurements. Data were analyzed using a 2-way analysis of variance test. Significance level was set at P < .05. ResultsThere was no significant difference between or within operators in intraoral radiographs (P > .05 and the Gage R&R value was <30%). There were significant differences between and within operators for CBCT images (P < .05 and Gage R&R value was >30%). There were significant differences in the methods in terms of mean differences from the gold standard (P < .05). ConclusionsThis study showed that available CBCT scans with different FOVs can be used for working length measurement.